1. Field of the Invention
The present invention relates to a motorcycle with turbocharger including a turbocharger which compresses fuel air and supplies to an engine.
2. Description of the Related Art
In a vehicle such as a motorcycle, there is a case when a combination of a reduction in an engine exhaust rate and a turbocharger is used, namely, the reduction in the exhaust rate of the engine and an improvement in intake efficiency by the turbocharger are simultaneously performed to enable a fuel efficiency improvement and an output power increase of the engine being an internal combustion engine.
In case of a motorcycle mounting so-called a “turbo” which compresses intake air by using an exhaust stream, a turbocharger makes use of the exhaust stream, and therefore, it is necessary to connect to an exhaust pipe extending from a cylinder head. Besides, the turbocharger is a large-sized and heavy part, and therefore, it is desirable to dispose the turbocharger at a front and lower part of a cylinder, particularly, at a lower part of a vehicle body as much as possible as illustrated in Patent Document 1 (FIG. 5).
Besides, when a motorcycle is equipped with a turbocharger, control valves (control parts) such as a waste gate valve (WGV) and an air bypass valve (ABV) are used together. In case of the motorcycle, it is effective to dispose the turbocharger at a rear of a front wheel from a relationship of heat damage and a weight as it is disclosed in, for example, Patent Document 2. On the other hand, under a disposition relationship as stated above, it is easy to be affected by scattering stones and so on at a vehicle driving time, and therefore, it is necessary that dedicated protective parts are to be equipped, or the control parts are to be disposed at a position free from the influence so as to avoid the influence.
Further, in Patent Document 1, a turbocharger is attached at a position adjacent to a cylinder head of an engine. The turbocharger compresses outside air introduced from an air cleaner box by a compressor, and thereafter, cools by an intercooler to supply to the engine. The outside air compressed by the turbocharger is burned at the engine, and thereby, combustion efficiency is improved, and the fuel efficiency improvement and the output power increase are enabled.
[Patent Document 1] Japanese Laid-open Patent Publication No. 2009-173259
[Patent Document 2] Japanese Laid-open Patent Publication No. S60-240524
Air cleaned by an air cleaner is supplied to the turbocharger. In this case, an intake port to take the air into the air cleaner is disposed at a high position from the ground, at a rear surface of another part, or the like to prevent entering of water, mud, and so on. An air intake pipe connected to the turbocharger extends toward a front and lower part of an engine in a conventional air cleaner disposition, and an intake passage (pipe) becomes long. Besides, there are cases when an air cleaner capacity is sacrificed to set the intake port at a proper position, or a disposition is restricted resulting from a relationship with the other parts.
In particular, the control valves and so on are weak for shock caused by collision of the scattering stones and so on, therefore, the dedicated protective parts are provided as stated above, or a disposed position is devised so as to avoid the effect. However, when the dedicated parts are provided, a weight and cost increase in accordance with an increase in the number of parts. Otherwise, a connection pipe length between the turbocharger and the control valves cannot but become longer more than necessary because the turbocharger and the control valves are apart. Therefore, there are problems such that a proper control is difficult to be performed in addition to the increase in weight and cost.
Further, in the motorcycle with the turbocharger as stated above, an improvement in vehicle body stiffness is required in accordance with the improved output power. On the other hand, the fuel efficiency improvement is damaged if the vehicle body is increased in weight to improve the vehicle body stiffness. In the motorcycle with turbocharger, it is necessary to attain inconsistent requirements of the improvement in the vehicle body stiffness and a reduction in weight of the vehicle body.